[Intel-gfx] [PATCH 1/2] drm/i915/guc: Add GuC Load time to debugfs

[Chris Wilson]

Quoting Tvrtko Ursulin (2017-09-07 09:49:02)
> 
> On 07/09/2017 01:37, Anusha Srivatsa wrote:
> > Calculate the time that GuC takes to load.
> > This information could be very useful in
> > determining if GuC is taking unreasonably long time
> > to load in a certain platforms.
> 
> Do we need this in debugfs or a DRM_NOTE or something would be 
> sufficient if the load time is above certain threshold?
> 
> Also, what are the typical times here? Are jiffies precise enough? Could 
> be only 10ms granularity on some kernels.

Hear, hear. Aiming for jiffie resolution sets a very low bar.

Why is this important anyway? It shouldn't be on the critical path for
bringing up userspace (i.e. on the synchronous portion of boot/module
loading). Nor should it be delaying bringing up a screen, once the core
is initialised we should be able to bring up GT and the display in
parallel.
-Chris